Seal for rotary regenerator



Oct. 10, 1961 A. HESS 3,003,750

SEAL FOR ROTARY REGENERATOR Filed Sept. 8, 1958 3 Sheets-Sheet 1 55 haul a1" 35 Anion Hess Oct. 10, 1961 A. HESS 3,003,750

SEAL FOR ROTARY REGENERATOR Filed Sept. 8, 1958 3 Sheets-Sheet 2 Amozz Hess Patented Oct. 10, 1961 3,003,750 SEAL FOR ROTARY REGENERATOR Anton Hess, Parma, Ohio, assignor to Thompson Ramo Wooldridge Inc., a corporation of Ohio Filed Sept. 8, 1958, Ser. No. 759,708 2 Claims. (Cl. 257269) The present invention relates to improvements in rotary regenerators for use with gas turbines and more particularly to a regenerator having a matrix drum rotating through a partition between high pressure and low pressure chambers with an improved seal to prevent the escape of gas past the outer surfaces of the drum as it passes through the partition.

The invention especially contemplates use with a gas turbine provided with a combustor for supplying heated gases to the turbine and a compressor delivering compressed air to the combustor. A rotary regenerator is provided to transfer heat from the exhaust gases from the turbine of the air delivered from the compressor to the combustor. The regenerator includes a rotary matrix drum. The matrix drum is annular in shape and has a plurality of radial passages for the flow of gas and air. The walls of the passages become heated when exhaust gas flows through the passages and the walls then heat the air when it flows through the passages. The drum rotates through gas and air chambers so that the passages alternately receive a flow of gas or air. The drum is mounted for rotation in a housing provided with a high pressure, low temperature air chamber and a high temperature, low pressure gas chamber. Air flows from the compressor through the high pressure chamber of the regenerator, is heated by the regenerator drum, and flows into the combustor. The exhaust from the gas turbine flows through the low pressure chamber of the regenerator to heat the drum. Thus, as the matrix rotates, heat energy is transferred from the turbine exhaust to the compressed air.

A feature of the invention is the provision of an improved seal for sealing flat or curved planar surfaces of the rotating regenerator matrix drum as it passes through the partition between the chambers. The seal in the form taught by the invention provides a curtain of air flowing away from the seal into the high pressure chamber to prevent any leakage flow from the high pressure chamber to the low pressure chamber. The air curtain is formed by elongated nozzles positioned to direct a flow of air along the flat surfaces of the drum into the high pressure chamber where the air, which is'supplied from a separate source at a higher pressure than that supplied by the compressor, admixes with the compressor air and flows to the combustor. In one form of the invention the air curtain seal is combined in a unique manner with a sliding seal and the seals are held by a unit retainer provided with means to control the seal position relative to the drum surface.

Accordingly, an object of the invention is to provide an improved rotary regenerator construction having im-. proved performance characteristics and efiiciency due to the reduction of leakage past the regenerator drum at the seals.

A further object of the invention is to provide an improved seal construction for a rotary regenerator which may be used with a compressor for a gas turbine and which will prevent the escape of compressed air past the rotary regenerator drum from the air chamber of the regenerator thereby avoiding losing the work potential of the compressed air.

Another object of the invention is to provide an improved seal construction for an annular rotary regenerator drum having flat surfaces which functions to prevent the escape of pressurized air past the drum surfaces and which employs high pressure air which will mix with the air in the regenerator to flow On to the combustor to thereby utilize the energy of the air for the seal.

Another object of the invention is to provide an improved seal for a rotary regenerator drum which is capable of effective operation without suffering disadvantages due to the severe efliects of temperature change on the regenerator parts Other objects and advantages will become more apparent with the teaching of the principles of the invention in connection with the disclosure and showing of the preferred embodiment thereof in the specification, claims and drawings, in which:

FIGURE 1 is a somewhat schematic showing partially in section of a turbine and regenerator combination embodying the principles of the present invention;

FIGURE 2 is a plan view of a regenerator housing illustrating the relative location of the regenerator parts;

FIGURE 3 is a horizontal sectional view taken through one of the seals for the regenerator drum;

FIGURE 4 is a vertical sectional view taken along the line IVIV of "FIGURE 3;

FIGURE 5 is a vertical sectional line taken along line VV of FIGURE 6;

FIGURE 5a is an enlarged perspective view of one of the seals at a corner of the regenerator drum with parts being removed so that the relation between the sealing strips can be shown;

FIGURE 6 is a horizontal sectional view taken along line VIVI of FIGURE 5;

FIGURE 7 is a vertical sectional line taken along line VIIV II of FIGURE 6; and,

FIGURE 8 is a horizontal sectional line taken along line VIIVII of FIGURE 5.

As shown on the drawings:

FIGURE 1 illustrates a turbine assembly having a turbine section 6 with a turbine housing 8 and a turbine rotor 10 therein. The housing is provided with a gas inlet 12 supplied from a combustor 14 which is provided with fuel at 16. The turbine rotor is mounted on a shaft 18 which is suitably supported on bearings in the turbine housing 8, and which drives a compressor 29. The compressor has a housing 22 with a compressor rotor 24 therein. The compressor rotor is secured to the shaft 18 and draws air through an inlet 26 in the housing 22. The compressed air is delivered from the volute shaped chamber'of the housing 22 through a compressed air discharge conduit 28, which connects to a regenerator housing 30.

Within the regenerator housing 30 is a rotary annular shaped drum or matrix assembly 32 which will be described in detail. The matrix provides gas flow passages for the exhaust gas from the turbine and for the compressed air flow from the compressor with the same pas sages alternately accommodating the flow of gas and air as the matrix assembly is rotated within the housing 30,

as will be appreciated by those skilled in the art. The housing 30 is provided with a partition 34 dividing the housing into a high pressure, low temperature compartment 36 for compressed air and a high temperature, low pressure compartment 38 for exhaust gases. The partition is provided with seals 35 and 37, FIG. 2, which will be described in detail later. Compressed air flows radially through the matrix assembly 32 from the compressed air conduit 28 through a regenerator housing inlet 29, and out through a regenerator housing outlet port 39, through a conduit 40 leading to the combustor. Exhaust gas from the turbine flows radially outwardly through the matrix assembly. The gas leaves the turbine through an exhaust conduit 42, flows through an exhaust inlet port 43 leading into the regenerator housing, and flows out through an exhaust outlet port '44; leading from the regenerator housing. The regenerator housing, the partition and chambers are shown in FIGURE 2 with certain of the ports for the housing omitted, it being understood that they may be located on the sides or ends of the housing to permit flow through the matrix drum. The matrix assemblyor drum 32 is driven in rotation, such as by a pinion gear 33 on a driven shaft 33a and in mesh with a ring gear 60 on the drum.

It is important to prevent leakage from the high pressure air chamber 36 to the low pressure exhaust chamber 38. Leakage past the flat surfaces of the regenerator is prevented by the seals which are located where the regenerator drum passes through the partition 34.

The matrix assembly consists generally of an annularly shaped drum 32 which is rectangular in cross-section as illustrated in FIGURES 4, 5, and 7, with radial flow passages.

A form of the seal is shown in FIGURES 3 and 4 wherein a curtain of high pressure air is formed at the seal location to prevent the flow of air'from'the high pressure chamber 36 to the low pressure chamber 38. High pressure air is supplied from a separate source 45, at a pressure higher than the output of the compressor 20. The seal illustrated is the seal 35, located where the matrix drum 32 passes from the high pressure air chamber 36 to V the low pressure gas chamber 38.

An elongated nozzle 46 is mounted in a block 48 to open in a direction to direct a flow of air'along the outer surface 32a of the drum toward the high pressure chamber 36. Another nozzle 56 is located adjacent the inner surface 32b of the drum and is positioned 'to direct a curtain of air along the surface 32b toward the high pressure chamber 36. Similar elongated. nozzles are positioned above and below the matrix drum 32 adjacent surfaces 32c and 32d. The drum has planar surfaces on all sides and surfaces 32a and 3211 may be referred to as. curved planar and surfaces 320 and 32d as fiat planar.

These nozzles are supplied from high pressure air chambers 52 and 54 in the blocks of 48 and 51 which are arranged to surround the drum. The chambers such as 52 and 54 may be interconnected, and may extend continuously around the drum as shown in FIGURE 4. The chambers are supplied through a conduit 56 which receives compressed air such as from the source 45 shown in FIGURE 1 which is at a higher pressure than the air from the compressor 36. For purposes of assembly and construction, the air chambers and nozzles may be separate for each fiat surface of the matrix drum, such as shown in FIGURE 5. The illustration of FIGURE 4 is primarily to illustrate the principles'of operation.

' As illustrated by theflow arrows 58 a tangential flow issues from the nozzle 46 causing a high pressure curtain of air to be formed which flows inwardly and admixes with the air within the chamber to flow to the combustor. Thus, the energy of the high pressure airfor forming the seal is'not lost, but is utilized.

r In the form shown in FIGURES -.8, the principle .of the air curtain is employed in combination with a sliding seal.

The matrix drum 32 is illustrated in greater detail in FIGURES 5 and 7 with the center portion shown unsectioned, except for a small area in FIGURE 7, and being the location where the radial air passages accommodate the flow of air or hot gas. The matrix may have walls formed of shaped plates 32h which maybe corrugated or the like forming small radial passages. The center or matrix portion 32e is bounded by plates 32 and 32g on the upper and lower annular surfaces of the matrix and below the plate 32g is a ring gear 60 for driving the matrix drum in rotation. The plates 32 and 32g are annular in shape and have inner and outer surfaces which are rigid and form guides for positioning the seals in the form of FIGURES 5-8.

The seals are held in retainers 62 and 64 as shown at the sides of the drum in FIGURE 5 and at 66 and 68 as shown at the top and the bottom of the drum in FIG- URE 5. Each of the side retainers 62 and 64 is recessed at one end to permit the end retainers 66 and 63 to project'beyond the flat surfaces of the matrix dlnm, as shown in FIGURE 5. The top and bottom retainers with the seals may be constructed substantially identical with the side retainers and their seals, and therefore only the side seals need be described in detail. The retainers 62 and 64 are supported in holders 70 and 72 which are suitably mounted on the outer curved wall 30a and the partition 34 for the housing. The holders have sides 70a and 72a which face the high temperature, low pressure chamber 38 and are provided with elongated grooves holding spring-loaded seals 72 and 74 which bear against the retainers 62 and 64; At the other side, the holders have sides 70b and 72b with grooves also provided with seals and '82, with these seals facing the high pressure, low temperature side 36 of the partition.

The holders carrying the seals permit movement of the retainers normal to the drum surfaces. Forthis purpose, the retainers are urged toward the drum by springs 83 and 84. As shown in FIGURE 5, the upper retainer 66 and lower retainer 68 are held by similar holders and springs 36:: and 38a in the spaces 86 and 88 urge the retainers and their seals toward the drum. These springs may be wave type springs or the like, applying a gentle sealing pressure.

The retainers are provided with rubbing seals 9 and 92 which are comprised of a plurality of flat sealing strips held in channels 94 and 96 of the retainers 62 and 64. The strips may be held such as by a cross pin 97, illustrated in FIGURE 8.

The seals are formedof a tale or soap stone or the like, which permit rubbing sealing engagement with the matrix drum-and being formed of a soft material will not cause excessive wear, and will not'damage the material of the matrix or clog the passages.

A feature of the seals is their ability to seal the corners of the matrixdrum. This is achieved by overlapping the seal strips at their ends so that they form a continuous seal around the corner of'the drum and yet are capable of sliding with respect to each other. This over-lapping feature maybeutilized whether the sealing strips are formed of a mineral such as talc or are formed of flexible high temperature metallic strips.

FIGURE 5a illustrates the relationship of the strips at the corner of the drum. The strips in this figure are not shown as having accurate dimensions, since theshowing is primarily to illustrate the relationship of the strips at the corner, and it will be understood that the strips extend for -a sufficient lengthin each direction so as to meet strips extending across an adjoining surface of the matrix drum. 7

A stack of strips 99 will be located on one surface of the matrix drum, and'a stack of strips 101 will be located against the adjoining surface of the drum. The inner edges of the stacks 99a and 101a willbe in sliding contact with the drum surface, if mineral strips are used or will be in close adjacency to the surface or. in light rubbing,

engagement therewith if metal strips are used. An upper strip 103 of the stack 99 is shifted so that the strip 105 can extend past an end 103a of the strip 103. An end 105a of the strip 105 extends completely to the end of the stack. Strips 107 and 109 are located directly adjacent strips 103 and 105, respectively. These strips are shifted in the opposite direction so that strip 107 extends with its end 107a to the end of the stack past an end 109a of the strip 109. Each stack has its strips alternately shifted or staggered so that the ends are in over-lapping relationship with the ends from the other stack. The overlapping ends can shift slightly with respect to each other, thus achieving a flexible stack arrangement and a tight seal at the corners of the drum. It will be understood that the ends of the strips are positioned to be slightly short of the strips against which they abut at the beginning of operation so that as the edges of the strips wear in, the ends will permit movement of the strips inwardly toward the drum.

The retainers are positively located with respect to the drum surfaces and for this purpose the retainer 62 has rollers 98 and 100 rotatably mounted at its lower end and similar rollers 102, 102 at the upper end. The retainer 64 has rollers 104 and 106 at the lower end and similar rollers 108, 108 at the upper end. The rollers bear against the hard, smooth, annular surfaces of the rings 32 and 32g at the top and bottom of the matrix drum, as illustrated in FIGURE 7.

The purpose of the rollers is two-fold. The rollers first maintain a constant clearance between the surfaces of the drum and the retainer. In the event labyrinth-type sealing strips are used in place of the soft talc strips, the rollers maintain a constant clearance between the drum and sealing strips. This type of sealing strip would employ the flexible metallic strip, instead of the soft rubbing strip. When a rubbing-type seal formed of a mineral, such as is shown in the drawings, is employed, the rollers prevent any further wear beyond the wear-in allowed for.

The second purpose of the rollers is to reduce the drag on the drum. The rollers present a rolling friction which is less than the sliding ooeflicient of friction, which, of course, results in longer wear and added insurance to prevent seizing and galling between the two surfaces at the contact point, especially where high temperatures and high Hertz stresses are involved.

A curtain of pressurized air formed by a high pressure air stream flowing toward the high pressure chamber is provided. The nozzles 110 and 1112 are positioned between the sliding seals 90 and 92 and the high pressure chamber 66, and open in the direction of the high pressure chamber to cause a flow of air along the surface of the drum. Thus, as illustrated in FIGURE 6, air will flow along the clearance spaces 114 and 116 to enter the high pressure chamber and prevent the escape of air from the high pressure chamber toward the low pressure chamber. The rollers are separated so that the air can directly enter the chamber as illustrated in the sectional view of FIG- URE 8. Air is supplied from chambers 118 and 120 leading to the nozzles which individually supply the nozzles to form a substantially continuous stream of air into the high pressure chamber. The high pressure air admixes with the air in the high pressure chamber and thus the energy of the air used for the seal is utilized.

In operation of the seal shown in FIGURES 5-8, the matrix drum 32 rotates in the direction indicated by the arrow from the low pressure chamber 38 to the high pressure chamber 36. A seal is provided by stacked strips 90 and 92 in edge engagement with the matrix and another seal is provided by the nozzles 110 and 112 which direct an elongated curtain of air into the high pressure chamber to admix with the air therein. The spacer rolls hold the clearance space between the nozzle and the drum surface and the retainers 62 and 64 carrying the nozzles are gently urged against the matrix by pressure springs.

It will be understood that a sealing arrangement similar to that shown in FIGURES 6 and 8 may be used on the top and bottom flat surfaces of the matrix drum. ,The construction will be substantially identical to that shown, with rollers bearing on the flat surfaces and strips engaging the surfaces and with air nozzles directing air in the same direction as the side air nozzles. Since the structure is substantially identical, the showings of FIGURES 6 and 8 will sutfice, as will be understood by those skilled in the art.

Thus, it will be seen that I have provided an improved matrix assembly having a seal meeting the objectives and advantages hereinbefore set forth. The mechanism attains an improved seal well suited to accommodating the distortions and changes in dimensions as occur with temperature change in a regenerator. The seal employs a flow of high pressure air and the energy of the air is utilized by admixing in the high pressure compressed air chamber.

I have, in the drawings and specification, presented a detailed disclosure of the preferred embodiments of my invention, and it is to be understood that I do not intend to limit the invention to the specific forms disclosed, but intend to cover all modifications, changes and alternative constructions and methods falling within the scope of the principles taught by my invention.

I claim as my invention:

1. A seal for hearing against the moving surface of a drum of a regenerator having a high and a low pressure chamber, an annular support having an inwardly facing channel for extending around the surfaces of an annular drum in a radial direction, side retainers mounted in said channel for relative radial movement therein toward the surfaces of the annular drum, seals between the sides of the retainers and the sides of the channel accommodating movement of the retainers toward or away from the drum, a series of stacked adjacent radial strips provided for each of the surfaces of the drum and mounted on the retainers, biasing means between the support and the retainers urging the retainers inwardly to move the strips in edgewise relationship against the drum surface, elongated nozzle means mounted in said side retainers and extending annularly around the drum in a radial direction and positioned to direct a flow of high pressure air along the surface of the drum, means for supplying a flow of high pressure air to said nozzles so that a curtain of air will flow along the drum away from the sealing strips, a first set of rollers mounted on the retainers outwardly of the air nozzles at one side of the retainers, and a second set of rollers spaced circumferentially of the first set at the other side of the retainers, said rollers having a fixed position relative to said retainers to positively fix the location of the retainers and be held against the drum by the biasing means and to engage the drum with a rolling friction.

2. A regenerator assembly comprising in combination a regenerator housing having a partition dividing the housing into a high pressure chamber and a low pressure chamber with a pair of spaced openings through the partition, inlet and outlet means for each of the chambers, an annular matrix drum having annular radially facing inner and outer surfaces and axially facing upper and lower surfaces and being rotatably positioned within the housing to move through the openings in the partition, a rigid ring for the drum having annular radially facing inner and outer surfaces conforming with the inner and outer surfaces of the drum, a seal positioned at a sealing location where the drum passes through one of the openings in the partition, said seal including a retainer assembly extending annularly in a radial direction around the surfaces of the matrix drum having end retainers positioned axially above and below the drum and having a side retainer positioned radially outwardly of the drum and another side retainer positioned radially inwardly of the drum with said side and end retainers movable with respect to each other and to the drum, a stack of rigid one-piece sealing strips rigidly held in each of the side retainers and in each of the end retainers with each stack extending completely across a' drum surface in sealing relationship with, the drum and movable with respect to each other with the retainers, spring members for each of the retainers between the partition and each of the end and side retainers urging the retainers individually toward the drum, retainer'seal-s permitting movement of the side and end retainers toward the drum and preventing the flow of gas between the retainers and the partition, circumferentially spaced drum engaging members carried by each of the side retainers at opposite circumferential sides of the side retainers engaging the inner and the outer surfaces respectively of said ring with the members for one side retainer at a radial location opposing the members of the other side retainer, said drum engaging members operating to define a spacing between the side retainers and inner and outer drum surfaces and to prevent the side retainers from tiltingwith respect to the inner and outer drum surfaces about an axis parallel to the drum axis, elongated air nozzles supported by said side retainers and located between the sealing strips and high pressure chamber and positioned to direct a curtain of air along the inner and outer drum surfaces toward the high pressure chamber to mix with the air therein, and means for supplying a continuous flow of air to said nozzles at a pressure higher than the pressure Within said high pressure chamber.

References Cited in the file of this patent UNITED STATES PATENTS 2,494,971 Summers Jan. 17, 1950 2,584,513 Summers Feb. 5, 1952 2,667,034- A1cock Jan. 26, 1954 2,747,843 Cox May 29, 1956 2,846,195 Alcock Aug. 5, 1958 2,865,611 Bentele Dec. 23, 1958 2,888,248 Bubniak et al May 26, 1959 FOREIGN PATENTS 649,265 Great Britain Jan. 24, 1951 651,771 Great Britain Apr. 11, 1951 679,169 reat Britain Sent. 17, 1952 

